On Tue, 21 Feb 2017 19:22:31 -0500, wrote:

On Tue, 21 Feb 2017 14:38:25 -0600, philo wrote:


Just realized . To me, using two different gauges is not a good idea.

If you use 12 and 14 the circuit breaker could not exceed 15 amps due to
the #14 wire. Since the breaker cannot exceed 15 amps then there is no
need to use #12 wire.


Additionally , somewhere down the road another owned of the house while
working in the breaker box might see the #12 wire on a 15 amp breaker
and put it on a 20 amp.


You would usually see this to mitigate voltage drop issues on a long
run of wire.
Say you had a 15a "outside" circuit and you want to extend that to a
shed 100 feet away, you might want to run that extension in #12.
A place you could see in commercial would be a run of wire through an
area with very high ambient temperatures like a roof top, where you
have to derate the wire on that run.
That too.